The number of total knee joint replacement operations performed throughout the world is large and growing. In 1989 approximately 250,000 of such operations were performed worldwide, roughly half of them being performed in the United States. The majority of total knee replacements require resurfacing of the patella, which involves removing a several millimeters thick section of the bone and cartilage from the articular surface and replacing the removed section with a plastic implant, which is cemented to the vestigial patella. The section is usually removed by cutting it with a saw, one member of the surgical team holding the patella by hand and another member making a free hand saw cut.
The success of the resurfacing procedure requires that the patella be cut such that the vestigial patella is of the correct thickness and the sawn surface is flat, even and properly oriented. The most common complications after total knee replacement involve the patella. It is believed that many of those complications are a result of inconsistent and poorly aligned saw cuts of the patella. Thus far no instrument for aiding the surgeon in making the required saw cut of the patella has proven satisfactory.